As an American married to an Englishman, I had to take the inaptly-named "Life in the UK" test.

Just wanted to reassure you that while my husband also failed the practice quiz (as did every Brit I asked the questions of), it's really not that bad! Buy the official handbook, read it a few times, invest a few hours in the practice tests, and you'll fly through. I was done with exam (and confident in reviewing my answers) in something like seven minutes. They give you 30 or 40 minutes. Since you can skip the English language requirement by taking the exam, I think a lot of non-native speakers try to skip the English test and then struggle with the subtleties of the question language.

Note that the test changed in April, so you'll need the latest book (I heard that they weren't going to change much else for content, though).